Whoever called politics "the art of the possible" must have had a strange idea of what is possible or a strange idea of politics, where the impossible is one of the biggest vote-getters.
People can get the possible on their own. Politicians have to be able to offer the voters something that they cannot get on their own. The impossible fills that bill perfectly.
You want the government to create more jobs for people when there is widespread unemployment? It's been done. During the Great Depression of the 1930s, the government employed more young men in the Civilian Conservation Corps than there were in the Army. The money to pay for all this had to come from somewhere-- and that meant that there was less money left to employ other people in the private sector. While jobs created by the government may not have reduced total unemployment, these jobs increased votes for the administration, which is the real bottom line in politics.